Answer:
I don't have the number of cubes in each bag, but whichever bag had the most cubes would have the most kinetic energy as it falls
It is 4/10 of moles is this ane halp?
Answer : The correct options are,
and 
Explanation :
Single displacement reaction : It is a type of chemical reaction in which the more reactive element displaces the less reactive element.
Option A reaction : 
It is an example of double displacement reaction because in this reaction a positive cation and a negative anion of the two reactants exchange their places to form two new products.
Option B reaction : 
It is an example of single displacement reaction.
Option C reaction : 
It is an example of combination reaction because in this reaction two reactants react to give a single product.
Option D reaction : 
It is an example of decomposition reaction because in this reaction a single reactant decomposes into two or more products.
Option E reaction : 
It is an example of single displacement reaction because in this reaction the most react element, aluminium displaces the less reactive element, hydrogen.
Hence, the options B and E are single displacement reactions.
<span>Activity series of metals. it is a series of metals based on their reactivity from highest to lowest. Potassium occupies the top most level of reactivity. The reactivity means the ability to displace hydrogen gas from water and acid solutions.</span>